The present invention relates to recycling of expendables included in a copier, facsimile apparatus, laser printer or similar image forming apparatus and, more particularly, to a recyclable toner container storing toner to be replenished into a developing unit included in the image forming apparatus.
Today, recycling articles customarily disposed of as expendables is one of major social demands from the standpoint of the effective use of limited resources and environmental protection. In an image forming apparatus, for example, expendables including a photoconductive element and a toner container should preferably be recycled. The toner container, for example, may be collected and again filled with toner to be reused or may be shreded into pellets, melted, and then reclaimed in the form of a molding.
However, conventional toner container recycling schemes, whether they reuse collected toner containers or reclaim them, have the following problems (1)-(5) left unsolved.
(1) Generally, toner containers themselves are not standardized as to their configuration, size, material, etc. Specifically, each manufacturer produces toner cartridges of a particular configuration and size fitting for their own machines or products. In addition, even a single manufacturer often varies the configuration and size of toner cartridges, depending on the type of machines. It is therefore difficult to collect a great number of toner containers of identical configuration, and therefore to efficiently reuse toner containers. These problems will be solved if all the different types of machines share a single kind of toner containers identical in configuration, size, material, etc. This kind of scheme surely increases the number of toner containers to be collected, and in addition reduces the production cost. However, when identical toner containers are shared by different types of machines, it is likely that a toner container storing a particular kind of toner is accidentally mounted to an image forming apparatus including a developing system expected to use a different kind of toner. In light of this, Japanese Patent Laid-Open Publication No. 7-168430 proposes to form each toner container with a lug at a particular position in order to indicate the kind of toner stored therein.
The approach taught in the above document successfully prevents the accidental setting of a toner container storing an unexpected kind of toner. However, the position of the lug and therefor the overall configuration differs from one toner container to another toner container. This prevents different types of a machines from sharing substantially all the toner containers, and therefore prevents a great number of toner containers to be collected and reused.
(2) The collected toner containers, whether they are to be reused or reclaimed, should be surely cleaned by air, water or the like in order to remove toner remaining therein. Assume that toner is left in a toner container collected and then refilled with toner. These, the toner is apt to cohere and reach a developing unit, resulting in a locally omitted solid image, as well known in the art. When toner is left in a toner container to be reclaimed in the form of a new molding, it is likely that the toner provides the molding with an unexpected characteristic or an unexpected color. For example, when the toner remaining in the toner cartridge is black, the molding expected to be white may become gray. In any case, it is not desirable to reuse or reclaims a toner container of low degree of cleaning.
Japanese Patent Laid-Open Publication Nos. 60-159769 and 7-159769, for example, each teaches a container for storing toner to be consumed or carrier to be deteriorated due to aging. The container is formed with a spiral ridge for a guide. While the container is in rotation, the spiral ridge drives toner or carrier toward an outlet formed in the container. A container lacking such a spiral ridge is also proposed. In any case, the container has a stepped portion between its body and the toner outlet. The toner outlet has a smaller diameter than the container body.
When the above container is collected and cleaned by water or air, the stepped portion and the small diameter of the toner outlet prevent toner or carrier remaining in the container from being fully removed despite repeated cleaning. Particularly, it is difficult to remove the entire toner or carrier remaining in the stepped portion and the bottom of the container and on the surfaces of the spiral ridge.
(3) When a collected toner container is to be reused after cleaning, whether or not it will withstand reuse must be determined by a test. This is because the dimensions of the container are apt to vary more than expected due to conditions in which the container was dealt with in the past. Particularly, the toner outlet or mouth of a toner container is apt to deform. If the diameter of the toner outlet is increased beyond a standard range, a cap fitted in the toner outlet at the time of reuse is apt to slip out and cause refilled toner to leak. Such a collected toner is not suitable for reuse and is excluded. This, however, reduces the number of containers which can be recycled, and thereby lowers profit. While the diameter of the toner outlet is measured by a contact type test, the measurement is not easy because the container is generally soft and long.
(4) Whether or not a collected toner container will withstand reuse should preferably be determined without any test. Specifically, if how many times the collected container has been reused in the past is known, containers reached a preselected frequency of recycling can be readily delivered to a reclaiming line and used as a reclaimed material for a new molding, However, this kind of implementation has not been reported yet.
(5) The State government of California, U.S.A, enforced a plastic container control law in June, 1995 in relation to the reclamation of toner containers not withstanding further reuse. The control law prescribes the use of PCR (Post Consumer Resin). PCR is produced when, e.g., a used hard polyethylene resin container (HDPE) is cleaned and then shreded, melted and pelletized after the removal of a label. PCR, however, cannot restore the natural color of a virgin material, but appears yellow-gray, despite the careful cleaning of the collected container. This is because toner remaining in the collected container cannot be fully removed by cleaning and is introduced into resin chips. As a result, PCR or reclaimed material varies in melt flow rate, fluxural strength, deflection temperature under load, specific gravity, and so forth, compared to a virgin material. The problem is therefore whether or not PCR can be handled in the same manner as a virgin material. Particularly, when the container formed of such a material is applied to an image forming apparatus, it must have an acceptable degree of flame retardation.